My DS was around the 75th in the early days but has been around 50th since about one and stayed there.
I'd just keep an eye on it and if it keeps dropping then talk to your dr about possible reasons but otherwise if it plateaus then don't stress.
Food before one is just for fun, milk still is their primary source of nutrition so if he doesn't want food don't stress.
Teething sucks because it completely messes with them. DS has never been a big milk drinker but a good eater since he weaned at 22mths but when he's cutting teeth he stops eating and just wants milk.
Hang in there and trust your instincts.